a. Field of the Invention
The present invention relates generally to an apparatus for mixing mortar, cement, and similar materials, and, more particularly, to a portable mixer for preparing such materials in ordinary disposable plastic buckets.
b. Related Art
Certain materials and compositions require mixing prior to use, particular examples of such materials being grout, mortar, plaster and cement. For example, masonry work or tile work typically requires that the mortar or grout be mixed at the jobsite immediately before use.
Unlike concrete, which is typically obtained in large volumes from a ready-mix plant or a mixer truck, mortar and grout work employ fairly small batches of material. For example, a brick mason or tile setter will typically prepare a small batch or mortar or grout for work at a first job site and then move to another job site and prepare another batch of material, as, for example, when moving from one house to another in a subdivision that is under construction.
Consequently, both portability and the ability to prepare small batches of material quickly and efficiently are important factors. Cost is also a significant important factor, particularly since many or most brick masons and tile setters are independent professionals who must buy all of their own equipment.
Currently available mixers do not adequately satisfy the foregoing criteria. Mortar or grout can, of course, be mixed the “old fashioned” way simply using a bucket and trowel, however this is neither convenient nor efficient, except for very small amounts of material. On the other hand, existing motor-driven mixers are expensive and lack adequate portability. For example, conventional mixers typically employ comparatively large steel or plastic drums that are rotated by an attached drive. Not only are the mixers themselves bulky and difficult to transport they are also cumbersome to use, since the drum must be dumped out into a smaller, second container (such as a bucket or tray) from which the mortar/grout is then applied. Moreover, the entire drum must be rinsed out and cleaned between jobs, lest it become encrusted with hardened material.
Another category of mortar/grout mixing devices employ rotating blades that are mounted on the end of a long shaft and driven by an electric motor, somewhat resembling an outsized paint mixer driven by an electric drill. These are inserted into tubs so as to generate a stirring action that mixes the components. In practice, however, this class of devices is highly unsatisfactory for several reasons, including inadequate mixing of the materials and the messy, cumbersome and physically tiring action that is inherent in their operation; moreover, the fact that they are manually operated means that other work must be stopped while the mortar/grout is being mixed. Another existing device resembles a small “roto-tiller” that mixes the material in a plastic trough, which combines the drawbacks of the “electric drill” type mixers with the cost, portability and cleaning problems associated with drum mixers.
Accordingly, there exists a need for an apparatus for mixing mortar, grout, and similar materials that is portable and readily transportable for going from one job site to the next. Furthermore, there is a need for such an apparatus that is convenient and easy to operate, yet which provides thorough mixing of the material. Still further, there is a need for such an apparatus that does not require the mortar, grout or other mixed material to be pumped into a separate container for use. Still further, there exists a need for such an apparatus that is inexpensive, requires minimal maintenance, and is long lasting in use.